Skip to content
WCAG 2 Test Rules

For developers of evaluation tools and test methodologies

About WCAG 2 Test Rules

Proposed audio or video that plays automatically has a control mechanism

Description

audio or video that plays automatically must have a control mechanism.

Applicability

This rule applies to any audio or video element for which all the following are true:

Expectation 1

For each test target, there is at least one instrument in the same web page to pause or stop the audio, or turn the audio volume off independently from the overall system volume control.

Expectation 2

The instrument to pause or stop or turn the audio volume off is visible, has an accessible name that is not only whitespace, and is included in the accessibility tree.

Assumptions

There are currently no assumptions

Accessibility Support

The native video and audio controls in several browser and assistive technology combinations are not keyboard accessible and the video or audio element itself may not be announced. Authors are recommended to use custom controls for keyboard navigation and cross browser accessibility support in general.

Background

Bibliography

Accessibility Requirements Mapping

Input Aspects

The following aspects are required in using this rule.

Test Cases

Passed

Passed Example 1

Open in a new tab

This audio element has an instrument to pause, stop, or turn the audio volume off.

<audio src="/test-assets/moon-audio/moon-speech.mp3" autoplay controls></audio>

Passed Example 2

Open in a new tab

This video element has an instrument to pause, stop, or turn the audio volume off.

<video autoplay controls>
	<source src="/test-assets/rabbit-video/video.mp4" type="video/mp4" />
	<source src="/test-assets/rabbit-video/video.webm" type="video/webm" />
</video>

Passed Example 3

Open in a new tab

This video element has a custom instrument to pause or stop or turn the audio volume off.

<head>
	<style>
		button {
			color: #000;
		}
		button:hover {
			cursor: pointer;
			cursor: pointer;
			background-color: grey;
			color: white;
		}
	</style>
</head>
<body>
	<div id="video-container">
		<!-- Video -->
		<video id="video" autoplay>
			<source src="/test-assets/rabbit-video/video.mp4" type="video/mp4" />
			<source src="/test-assets/rabbit-video/video.webm" type="video/webm" />
		</video>
		<!-- Video Controls -->
		<div id="video-controls">
			<button type="button" id="play-pause" class="play">Pause</button>
			<button type="button" id="mute">Mute</button>
		</div>
	</div>
	<script src="/test-assets/80f0bf/no-autoplay.js"></script>
</body>

Failed

Failed Example 1

Open in a new tab

This audio element does not have an instrument to pause, stop, or turn the audio volume off.

<audio src="/test-assets/moon-audio/moon-speech.mp3" autoplay></audio>

Failed Example 2

Open in a new tab

This video element autoplays and does not have an instrument to pause, stop, or turn the audio volume off.

<video autoplay>
	<source src="/test-assets/rabbit-video/video.mp4" type="video/mp4" />
	<source src="/test-assets/rabbit-video/video.webm" type="video/webm" />
</video>

Failed Example 3

Open in a new tab

This video element has an instrument to pause, stop, or turn the audio volume off but the instrument is not visible.

<head>
	<style>
		button {
			color: #000;
			display: none;
		}
		button:hover {
			cursor: pointer;
			cursor: pointer;
			background-color: grey;
			color: white;
		}
	</style>
</head>
<body>
	<div id="video-container">
		<!-- Video -->
		<video id="video" autoplay>
			<source src="/test-assets/rabbit-video/video.mp4" type="video/mp4" />
			<source src="/test-assets/rabbit-video/video.webm" type="video/webm" />
		</video>
		<!-- Video Controls -->
		<div id="video-controls">
			<button type="button" id="play-pause" class="play">Pause</button>
			<button type="button" id="mute">Mute</button>
		</div>
	</div>
	<script src="/test-assets/80f0bf/no-autoplay.js"></script>
</body>

Failed Example 4

Open in a new tab

This video element has an instrument to pause, stop, or turn the audio volume off but its button elements do not have accessible names.

<head>
	<style>
		button {
			color: #000;
		}
		button:hover {
			cursor: pointer;
			cursor: pointer;
			background-color: grey;
			color: white;
		}
	</style>
</head>
<body>
	<div id="video-container">
		<!-- Video -->
		<video id="video" autoplay>
			<source src="/test-assets/rabbit-video/video.mp4" type="video/mp4" />
			<source src="/test-assets/rabbit-video/video.webm" type="video/webm" />
		</video>
		<!-- Video Controls -->
		<div id="video-controls">
			<button type="button" id="play-pause" class="play"></button>
			<button type="button" id="mute"></button>
		</div>
	</div>
	<script src="/test-assets/80f0bf/no-autoplay.js"></script>
</body>

Failed Example 5

Open in a new tab

This video element has an instrument to pause, stop, or turn the audio volume off but the instrument is not included in the accessibility tree.

<head>
	<style>
		button {
			color: #000;
		}
		button:hover {
			cursor: pointer;
			cursor: pointer;
			background-color: grey;
			color: white;
		}
	</style>
</head>
<body>
	<div id="video-container">
		<!-- Video -->
		<video id="video" autoplay>
			<source src="/test-assets/rabbit-video/video.mp4" type="video/mp4" />
			<source src="/test-assets/rabbit-video/video.webm" type="video/webm" />
		</video>
		<!-- Video Controls -->
		<div id="video-controls" aria-hidden="true">
			<button type="button" id="play-pause" class="play">Play</button>
			<button type="button" id="mute">Mute</button>
		</div>
	</div>
	<script src="/test-assets/80f0bf/no-autoplay.js"></script>
</body>

Inapplicable

Inapplicable Example 1

Open in a new tab

The audio of this video element autoplays for longer than 3 seconds but is muted.

<video autoplay muted>
	<source src="/test-assets/rabbit-video/video.mp4" type="video/mp4" />
	<source src="/test-assets/rabbit-video/video.webm" type="video/webm" />
</video>

Inapplicable Example 2

Open in a new tab

The src file of this video element has no audio output.

<video autoplay>
	<source src="/test-assets/rabbit-video/video-with-incorrect-voiceover.mp4" type="video/mp4" />
	<source src="/test-assets/rabbit-video/video-with-incorrect-voiceover.webm" type="video/webm" />
</video>

Inapplicable Example 3

Open in a new tab

This audio element does not autoplay.

<audio src="/test-assets/moon-audio/moon-speech.mp3" controls></audio>

Glossary

Accessible Name

The accessible name is the programmatically determined name of a user interface element that is included in the accessibility tree.

The accessible name is calculated using the accessible name and description computation.

For native markup languages, such as HTML and SVG, additional information on how to calculate the accessible name can be found in HTML Accessibility API Mappings 1.0, Accessible Name and Description Computation (working draft) and SVG Accessibility API Mappings, Name and Description (working draft).

For more details, see examples of accessible name.

Note: As per the accessible name and description computation, each element always has an accessible name. When no accessible name is provided, the element will nonetheless be assigned an empty ("") one.

Note: As per the accessible name and description computation, accessible names are flat string trimmed of leading and trailing whitespace. Notably, it is not possible for a non-empty accessible name to be composed only of whitespace since these must be trimmed.

Attribute value

The attribute value of a content attribute set on an HTML element is the value that the attribute gets after being parsed and computed according to specifications. It may differ from the value that is actually written in the HTML code due to trimming whitespace or non-digits characters, default values, or case-insensitivity.

Some notable case of attribute value, among others:

This list is not exhaustive, and only serves as an illustration for some of the most common cases.

The attribute value of an IDL attribute is the value returned on getting it. Note that when an IDL attribute reflects a content attribute, they have the same attribute value.

Focusable

An element is focusable if one or both of the following are true:

Exception: Elements that lose focus during a period of up to 1 second after gaining focus, without the user interacting with the page the element is on, are not considered focusable.

Notes:

Included in the accessibility tree

Elements included in the accessibility tree of platform specific accessibility APIs are exposed to assistive technologies. This allows users of assistive technology to access the elements in a way that meets the requirements of the individual user.

The general rules for when elements are included in the accessibility tree are defined in the core accessibility API mappings. For native markup languages, such as HTML and SVG, additional rules for when elements are included in the accessibility tree can be found in the HTML accessibility API mappings (working draft) and the SVG accessibility API mappings (working draft).

For more details, see examples of included in the accessibility tree.

Programmatically hidden elements are removed from the accessibility tree. However, some browsers will leave focusable elements with an aria-hidden attribute set to true in the accessibility tree. Because they are hidden, these elements are considered not included in the accessibility tree. This may cause confusion for users of assistive technologies because they may still be able to interact with these focusable elements using sequential keyboard navigation, even though the element should not be included in the accessibility tree.

Instrument to achieve an objective

An HTML element that when activated allows an end-user to achieve an objective.

Note: Any rule that uses this definition must provide an unambiguous description of the objective the instrument is used to achieve.

Outcome

An outcome is a conclusion that comes from evaluating an ACT Rule on a test subject or one of its constituent test target. An outcome can be one of the three following types:

Note: A rule has one passed or failed outcome for every test target. When there are no test targets the rule has one inapplicable outcome. This means that each test subject will have one or more outcomes.

Note: Implementations using the EARL10-Schema can express the outcome with the outcome property. In addition to passed, failed and inapplicable, EARL 1.0 also defined an incomplete outcome. While this cannot be the outcome of an ACT Rule when applied in its entirety, it often happens that rules are only partially evaluated. For example, when applicability was automated, but the expectations have to be evaluated manually. Such “interim” results can be expressed with the incomplete outcome.

Programmatically Hidden

An HTML element is programmatically hidden if either it has a computed CSS property visibility whose value is not visible; or at least one of the following is true for any of its inclusive ancestors in the flat tree:

Note: Contrarily to the other conditions, the visibility CSS property may be reverted by descendants.

Note: The HTML standard suggests rendering elements with the hidden attribute with a CSS rule that applies the value none to the CSS property display of the element. Although the suggestion is not normative, known user agents render it according to the suggestion (unless the content specifies another CSS rule that sets the value of the display property). If a user agent does not follow the suggestion, this definition may produce incorrect results for this user agent.

Visible

Content perceivable through sight.

Content is considered visible if making it fully transparent would result in a difference in the pixels rendered for any part of the document that is currently within the viewport or can be brought into the viewport via scrolling.

Content is defined in WCAG.

For more details, see examples of visible.

Web page (HTML)

An HTML web page is the set of all fully active documents which share the same top-level browsing context.

Note: Nesting of browsing context mostly happens with iframe and object. Thus a web page will most of the time be a “top-level” document and all its iframe and object (recursively).

Note: Web pages as defined by WCAG are not restricted to the HTML technology but can also include, e.g., PDF or DOCX documents.

Note: Although web pages as defined here are sets of documents (and do not contain other kind of nodes), one can abusively write that any node is “in a web page” if it is a shadow-including descendant of a document that is part of that web page.

Whitespace

Whitespace are characters that have the Unicode “White_Space” property in the Unicode properties list.

This includes:

Implementations

There are currently no known implementations for this rule. If you would like to contribute an implementation, please read the ACT Implementations page for details.

Changelog

This is the first version of this ACT rule.

Back to Top

This is an unpublished draft preview that might include content that is not yet approved. The published website is at w3.org/WAI/.